wakebum2507
New member
long story short, recently bought a Formula 330SS, so i'll be getting rid of the Formula 252BR. took it out last weekend, boat doesn't want to get over 3600 or so RPM. i've read a few threads on here, but wanted some input on what else i could potentially troubleshoot.
Current plan of attack:
-new fuel/water separator
-did these Merc's have in-line fuel filters? if so, i'll change that too
-new lines. I believe they're OEM hard lines, and could be gunked up.
-check for spark on each cylinder
it could be that the second butterflies aren't opening on the carb, but its my understanding that they will only open at load, under RPM:
"2. Secondary base plate (bottom) butterflies open mechanically, The upper secondary butterflies (large) open on vacuum demand based on load.
They typically will NOT open unless under load. When they open this is what allows the additional fuel. If they do not open then no additional fuel.
They are controlled by a small spring (wound and round) which is adjustable."
its got thru-drive/prop exhaust, so i don't think theres a restriction there.
it does have a slight miss/stall when at somewhere around 1200-1500 RPM, which seems fuel related to me. but could be spark?
I read another post here, which turned out to be the timing/ignition sensor/module, so thinking MAYBE that, but want to see if its getting good fuel first.
The post:
"Disconnected the knock sensor to take that out of the equation. Confirmed good spark to all cylinders. When he revered up to 3000 RPM initially the timing went up with the revs to 30 degrees but staying at 3000 or trying to go over, or going down and back up to 3000 the timing was falling all the way back to almost TDC and staying down there. He determined it did not need to stay up at 30 but basically no way the boat was going to run right if the timing kept falling and staying that low. ...after falling back low .it seemed like timing was not advancing at all to significant throttle and engine RPM increases."
what are the thoughts? do i have the right process of evaluation/troubleshooting? boat runs fine, no knocking, to 3600 or so, then just doesn't want to pull any more RPM.
Current plan of attack:
-new fuel/water separator
-did these Merc's have in-line fuel filters? if so, i'll change that too
-new lines. I believe they're OEM hard lines, and could be gunked up.
-check for spark on each cylinder
it could be that the second butterflies aren't opening on the carb, but its my understanding that they will only open at load, under RPM:
"2. Secondary base plate (bottom) butterflies open mechanically, The upper secondary butterflies (large) open on vacuum demand based on load.
They typically will NOT open unless under load. When they open this is what allows the additional fuel. If they do not open then no additional fuel.
They are controlled by a small spring (wound and round) which is adjustable."
its got thru-drive/prop exhaust, so i don't think theres a restriction there.
it does have a slight miss/stall when at somewhere around 1200-1500 RPM, which seems fuel related to me. but could be spark?
I read another post here, which turned out to be the timing/ignition sensor/module, so thinking MAYBE that, but want to see if its getting good fuel first.
The post:
"Disconnected the knock sensor to take that out of the equation. Confirmed good spark to all cylinders. When he revered up to 3000 RPM initially the timing went up with the revs to 30 degrees but staying at 3000 or trying to go over, or going down and back up to 3000 the timing was falling all the way back to almost TDC and staying down there. He determined it did not need to stay up at 30 but basically no way the boat was going to run right if the timing kept falling and staying that low. ...after falling back low .it seemed like timing was not advancing at all to significant throttle and engine RPM increases."
what are the thoughts? do i have the right process of evaluation/troubleshooting? boat runs fine, no knocking, to 3600 or so, then just doesn't want to pull any more RPM.
